Timeline of DOS operating systems

This article presents a timeline of events in the history of 16-bit x86 DOS-family disk operating systems from 1980 to present. Non-x86 operating systems named "DOS" are not part of the scope of this timeline.

Also presented is a timeline of events in the history of the 8-bit 8080-based and 16-bit x86-based CP/M operating systems from 1974 to 2014, as well as the hardware and software developments from 1973 to 1995 which formed the foundation for the initial version and subsequent enhanced versions of these operating systems.

+ Color keyMicrosoft: 86-DOS, MS-DOSIBM: PC DOSDigital Research: CP/M, DR-DOSCompaq MS-DOSFreeDOS, GNU/DOSOther DOS releases have been in the forms of: OEM adaptation kits (OAKs) – all Microsoft releases before version 3.2 were OAKs only Shrink wrap packaged product for smaller OEMs (system builders) – starting with MS-DOS 3.2 in 1986,Microsoft offered these in addition to OAKs End-user retail – all versions of IBM PC DOS (and other OEM-adapted versions) were sold to end users.DR-DOS began selling to end users with version 5.0 in July 1990, followed by MS-DOS 5.0 in June 1991 Free download – starting with OpenDOS 7.01 in 1997, followed by FreeDOS alpha 0.05 in 1998(FreeDOS project was announced in 1994)

DOS era version overview (1980–1995)

+First end-user releases of IBM–Microsoft-compatible versionsMajor market-leading releases and releases introducing significant new technologyDateVersionPrimary developerNotable introductionIBM hardwareAugust 198086-DOS 0.10Tim PatersonFirst Seattle Computer releaseAugust 1981PC DOS 1.0MicrosoftFirst IBM releaseIBM Personal ComputerMay 1982PC DOS 1.1MicrosoftDouble-sided disksUpgraded IBM Personal ComputerMarch 1983PC DOS 2.0MicrosoftHard disk drive, subdirectories, device driversIBM Personal Computer XTNovember 1983PC DOS 2.1MicrosoftHalf-height disk drives, ROM cartridgesIBM PCjrAugust 1984PC DOS 3.0MicrosoftSupport for larger disksIBM Personal Computer/ATApril 1985PC DOS 3.1MicrosoftLocal area networking supportIBM PC NetworkMarch 1986PC DOS 3.2Microsoft3-inch 720 KB floppy supportToken Ring networkIBM PC ConvertibleApril 1987PC DOS 3.3IBM3-inch 1.44 MB floppy support, extended partitionsIBM Personal System/2November 1987MS-DOS 3.31CompaqHard disk partitions over 32 MBMay 1988DR DOS 3.31Digital ResearchROMable DOSJuly 1988IBM DOS 4.0IBMDOS Shell, EMS 4.0 usageApril 1990DR DOS 5.0Digital ResearchMemory managementJune 1991MS-DOS 5.0MicrosoftMS-DOS Editor, QBasic, first retail upgradeSeptember 1991DR DOS 6.0Digital ResearchDisk compression (AddStor's SuperStor)March 1993MS-DOS 6.0MicrosoftDisk utilities, DoubleSpace disk compressionJune 1993PC DOS 6.1IBMFirst IBM release after split with Microsoft, ESeptember 1993MS-DOS 6.2Microsoft Improved version of DoubleSpaceFebruary 1994MS-DOS 6.21Microsoft DoubleSpace removed due to legal injunctionApril 1994PC DOS 6.3IBMSuperStor/DS disk compressionJune 1994MS-DOS 6.22MicrosoftLast Microsoft release; DriveSpace disk compressionApril 1995PC DOS 7.0IBMMemory optimizations, Stacker disk compression, Rexx

1973–1980: Hardware foundations and CP/M